Speciation Analysis of Nickel in the Soils of Tejgaon Industrial Area of Bangladesh

Abstract

The main focus of the study is Tejgaon industrial area which is located within the Dhaka City Corporation and about 5 km north of the city centre. The industries around the study area like battery, chemical manufacturing, electrical and electronic, metal finishing, mining, paint and dye, textiles, pharmaceuticals, pesticides, etc, discharge heavy metals like Ni with their effluents and wastes. At Tejgaon soil the minimum pH value was 5.3 and the maximum 7.6 (at 26 O C). High buffering capacity resulting from high soil organic matter content (4.87-11.55%) probably influenced soil pH. Electrical conductivity (EC) (25-551 µS/cm) and organic matter (OM) (4.87-11.55%) contents were also influenced by the industrial wastes and effluents of the factories. In the wet season, the average Ni concentration in different soil fractions was 1.69, 4.16, 13.21 and 93.12 mg kg -1 in water-soluble, NH 4 OAC extractable, DTPA extractable and total fractions respectively. Comparing wet season and dry season sampling data, total Ni concentrations in different locations were higher in the dry season and the mean concentration of total Ni was 223.89 mg kg -1 , which was more than 4 times higher than the tolerable limit.Concentrations of total Ni in different locations during wet season were found above the natural background level with few exceptions. Ni concentration in the group of tolerable level was 21% (>022-<50 mg kg -1 ) and 75% (>50 mg kg -1 ) soil samples were found in the group of in excess of tolerable level during wet season. During dry season, 11% of Ni (<50 mg kg -1 ) samples were in the normal range and 89% (>50 mg kg -1 ) soil samples were found in the group of in excess of tolerable level. Ni concentration during dry season samples in different extraction i.e in NH 4 OAC extractable, DTPA extractable and in total fraction was found to decrease with distance away from the disposal point source due to dilution of the effluent and water. The decreasing tendency with distance indicates the accumulation of metals by the industrial operations.

Toxic metals (Ni2+, Pb2+, Hg2+) binding affinity of dissolved organic matter (DOM) derived from different ages municipal landfill leachate

“…The sources of these metals in leachate samples might be the damage batteries, broken thermometers, electronic devices etc. in the solid waste in landfill site (EDSO 2010;Chamon et al 2009). Pesticides also could be a source of metals in leachate that may come through the decomposition of discarded vegetables, fruits, etc.…”

“…All types of waste such as redundant vegetables, food, plastics bags, broken batteries, thermometers, chemical waste are discarded together without appropriate segregation. In addition various industries dispose heavy metals containing wastes (Chamon et al 2009). These wastes ultimately find their ways in different rivers, ponds, canals, roadside open spaces and only about half of them are dumped in open landfill sites as a cheapest mean of management (Ahmed and Ali 2006;Sujauddin et al 2008).…”

Accumulation of heavy metals on bed sediments of Nairobi dam, Kenya

“…A study by Mondol et al (2011) on seasonal variation of heavy metals concentrations in water and plant samples around Tejgaon industrial area of Bangladesh showed that in the rainy season the pollution was lower because heavy rainfall were flushed out through the canal into the adjoining vast flood zone. As the rainy season receded the soils and water were enriched with the pollution load (Chamon et al, 2009;Ullah et al, 1999).…”

Study of Surface Water and Soil Quality Affected by Heavy Metals of Pabna Sadar

“…Although the level of heavy metals in few selected areas of Bangladesh have been found in the literatures (Chamon et al,2009, Shamshad et al, 2005, Sultana et al, 2009& 2003, Ali et al 1998, Kashem et al, 1998, Alam et al 2002, Mahfuz et al, 2004, but no systematic work about it has done at Pabna Sadar. So it is necessary to assess the soil and water quality of this area to concern people as well as to protect environment.…”